Outdoor time, gut bacteria, and stress in young children's weight

Childhood Obesity: the role of the gut Microbiome, outdoor Time, and Stress(COMETS)

NIH-funded research Washington State University · NIH-11261597

This project looks at whether more outdoor time, healthier gut bacteria, and lower stress can help prevent or reduce obesity in young children, especially those from low-income families.

Quick facts

Grant typeR01 grant
Study typeNIH-funded research
Funding institutionWashington State University NIH-funded
Lab location1 site (Pullman, United States)
Project IDNIH-11261597 on NIH RePORTER

What this research studies

If your child joins, researchers will follow preschool-aged children over time and compare kids who spend more time in outdoor preschools with those in more typical settings. They will collect stool samples to study gut bacteria, take simple body measurements like height and weight, and measure stress markers such as cortisol. The team will also record how much time children spend outside and information about family and neighborhood conditions. The goal is to see if outdoor time helps build resilience to social and economic risk factors for childhood obesity.

Who could benefit from this research

Good fit: Ideal candidates are preschool-aged children (around 3–5 years old) and families, particularly those from lower socioeconomic backgrounds or who attend participating childcare or preschool programs.

Not a fit: Children with obesity caused by rare genetic disorders, older adolescents, or adults are unlikely to get direct benefit from this early-childhood-focused work.

Why it matters

Potential benefit: If successful, this work could support low-cost, practical approaches—like more outdoor preschool time—that reduce childhood obesity and improve gut and stress-related health in young children.

How similar studies have performed: Direct trials of outdoor preschools for obesity prevention are rare, but prior studies link nature exposure to increased gut microbial diversity and lower stress, giving preliminary support for this approach.

Where this research is happening

Pullman, United States

Researchers

About this research

  1. This is an active NIH-funded research project — typically early-stage science, not a clinical trial accepting patient enrollment.
  2. Some NIH-funded labs run parallel clinical studies or seek volunteers for related work. To check, contact the principal investigator or institution listed above.
  3. For full project details, budget, and progress reports, visit the official NIH RePORTER page below.
Last reviewed 2026-06-10 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.